OK - so, step 1 - find someone that fits that criteria. I'm focused on support nuances only (eg don't teach me how to adc better, teach me how to be a better support), so hopefully I can find someone that is an excellent support or adc. After doing some research, I came across this reddit site:
After searching for a bit, I literally found someone saying they were diamond elo and wanted to work with a Plat or > support to help them get better at support. I mean... the post literally said exactly what I was looking for. So, I add the guy and he comes online later. I hit him up and tell him I saw his post, I feel like I'm a decent support but I'd like to improve. We hop on voice chat an immediately get into a game with him as draven, me as thresh.
Now, I'm setting myself up at a slightly bigger disadvantage as I'm playing a little bit off. By that, I mean I'm a little nervous and not as comfortable due to playing with someone brand new and the big disparity in elo (guy peaked high diamond 1 and is currently diamond 3). So, I'm a little sheepish and not as decisive as I'd normally be in game 1.
Anyway, so the first thing he calls out is me having very weak lane control. He says its not about landing hooks as thresh - forget that crap. Its about presence and your flay. This guy seems to process the map information at a much higher rate than I typically do. 1 slight mistep from the enemy adc or support and he already has in mind exactly what he and I should have done (eg guy was just slightly too far head, I should be wailing on him and setting up a flay while he lands 2-3 AAs). It seems like really basic stuff, but he's seeing all of these very specific things for both roles. Me, I know if I set something up and my adc is a crap and gets no damage in, etc. This guy is on top of that, very briefly saw the enemy jungle at mid and is thinking about that, etc. Its just all at a higher speed that I usually function at. He's got an incredible understanding of wave management (I have a decent understanding - he is managed precisely down to the creep level) and is easily the most mechanically talented player I've played with.
Think of all of your general league knowledge for whatever role. Now, assume there are about 10 things you should be doing to probably do not. This guy seems to know those 10 things and you can pick up on them. But of course, its crap I didn't know I wasn't doing, so it wouldn't even occur to me. That's kind of what the whole experience has been. Good pacov support in my bucket is bad pacov support at higher bucket.
I'm trying to track all the things I'm learning. Alot of the focus is moreso on getting good wards in the enemy jungle more frequently and swinging the lane control wisely (not via hooks - you still go for hooks ofc). My need to upgrade relic shield has dropped off almost entirely as it can disrupt my adcs flow/control of the creep management - I instead look for a boots 2 rush or just stick with SS on 1st back. My ballsy all in plays that would work in my bucket don't pan out as well (we generally got kills based on my adcs high skill cap or me setting up added damage with a flay/hook combo). I'm sticking with a more common rune page including AD reds (not my adcs suggestion, just what I swapped to running).